The present application claims priority under 35 U.S.C. xc2xa7119 to Japanese Patent Application No. 2002-085680, filed Mar. 26, 2002, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a compact vehicle having a seat provided at the rear of a vehicle body and an air bag that can constrain a rider on the seat from a forward direction when the air bag is inflated and extended.
2. Description of Background Art
Such a compact vehicle is disclosed in Japanese published unexamined patent application No. 2001-219884 for example.
To enhance impact absorption in a four-wheel vehicle, an inflated and extended air bag and a seat belt made tense by the action of impact are required to be used together. In a compact vehicle such as a motorcycle, it is considered that the effect of an air bag can be more enhanced by using a seat belt disclosed in Japanese published unexamined patent application No. Hei8-239073. However, in the compact vehicle such as a motorcycle, a secondary motion such as an overturn or a skid after collision may occur, thus causing a secondary collision. In this case, it is desirable that constraint by a seat belt is released.
The invention is made in view of such a situation. The object of the invention is to provide a compact vehicle which enhances the impact absorption effect by an air bag for a rider constrained by a seat belt. When a secondary motion is caused in relation to a body, the seat belt constraining the rider can be released.
To achieve the object, a first aspect of the present invention is based upon a compact vehicle having a seat provided to the rear of a body and an air bag that can constrain a rider on the seat from a forward direction when the air bag is inflated and extended. One end of a seat belt, which can be wound around the waist of the rider on the seat, is coupled to the vehicle body via a retractor provided with a locking function in emergency. Further, a coupling means is provided in which coupling and the release of coupling can be switched manually. In addition, when the air bag is inflated and extended between the other end of the seat belt and the body, the coupling is automatically released after a predetermined period of time elapses.
According to such a configuration, when the air bag is inflated and extended because of the collision of the compact vehicle, the rider is constrained by the seat belt made tense when the retractor is locked by keeping the coupling means in the coupled state by manual operation. In this situation, impact can be effectively relieved because the inflated and extended air bag receives the rider constrained by the seat belt. In addition, since the coupling of the coupling means is automatically released after a predetermined period of time elapses when the air bag is inflated and extended, the seat belt constraining the rider is released.
According to a second aspect of the invention, the coupling of the coupling means is released when an overturn detection sensor for detecting the overturn of the body detects the overturn. According to such a configuration, when the motorcycle individually overturns because of a cause other than a collision, and a skid or a secondary collision occurs, the constraint of the rider on the body is released.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.